atm: iphase: fix possible use-after-free in ia_module_exit()

This module's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/atm/iphase.c b/drivers/atm/iphase.c
index e3f5d073caa65d7e796653edd2785583b82272a1..bc8e8d9f176b2c7b96f750f3e34e8e72a8355c71 100644 (file)
--- a/drivers/atm/iphase.c
+++ b/drivers/atm/iphase.c
@@ -3282,7 +3282,7 @@ static void __exit ia_module_exit(void)
 {
        pci_unregister_driver(&ia_driver);
 
-        del_timer(&ia_timer);
+       del_timer_sync(&ia_timer);
 }
 
 module_init(ia_module_init);